Clutch lockout mechanism

ABSTRACT

A clutch lockout includes posts to receive bolts to retain the lockout to a clutch boss and retaining screw holes to retain lockout fingers mounted on the lockout. At least one indent in each post accommodates the retaining screw holes.

TECHNICAL FIELD

The present disclosure relates to clutch systems.

BACKGROUND

In motorized vehicles, the clutch enables the engine drive train to bedisconnected from the axels during changes in the drive ratio. Often,the clutch provides a friction coupling between the drive train and theaxels. This friction coupling (for example, contact between twofiber-compound discs) may be prone to slipping as the drive trainrotations per minute (RPM) increase. To alleviate this condition, aclutch lockout may be employed.

FIGS. 1 and 2 are front and back view illustrations, respectively, of aprior art clutch lockout 100. The lockout 100 may be employed in two andfour stroke engine systems, such as Honda™ and Banshee™ motors for allterrain vehicles (ATVs). Bolts may be inserted through the holes 118 inthe posts 106 to mount the lockout 100 to a clutch boss of the engine.Heads of the bolts may recess into the counter-sink holes 120. The shaftof the bolts may pass through springs. As the bolts are tightened to theclutch boss, the springs come under tension, recessing the heads of thebolts into the holes 120, and bringing the posts 106 into contact with aclutch pressure plate.

FIG. 3 is a side view illustration of a lockout finger 300. The finger300 has an arm 306 and a cam 304. A bolt may be inserted through thehole 308 and secured with a nut to add weight to the end of the arm 306.A pivot may be inserted through the hole 302 at the juncture of the arm306 and the cam 304. Fingers 300 may be inserted into the slots 110 ofthe lockout 100 and the pivot may be recessed into the slots 112.Retaining screws may be threaded into the holes 114, and tightened untiltheir heads are recessed into the countersink holes 116, thus securingthe finger pivots in the slots 112.

Forming a hole 102 in the lockout 100 lessens the weight and mayaccommodate possible protrusions of the transmission system. Formingbays 108 also lessens the weight of the lockout 100.

As engine RPMs increase, the arms 306 of the fingers 300 are drawnoutward by centrifugal force, rotating the cam 304 against a pressureplate mounted behind the lockout 100. Rotation of the cams 304 againstthe pressure plate increases the force of the frictional couplingbetween the engine drive train and the axels, reducing slipping of theclutch at higher engine RPMs.

Weight and durability of system components are crucial factors in theperformance of engine systems. An improved lockout would benefit fromfurther reductions in weight, while either improving or withoutcompromising the durability of the lockout.

SUMMARY

The following summary is intended to highlight and introduce someaspects of the disclosed embodiments, but not to limit the scope of theinvention. Thereafter, a detailed description of illustrated embodimentsis presented, which will permit one skilled in the relevant art to makeand use aspects of the invention. One skilled in the relevant art canobtain a full appreciation of aspects of the invention from thesubsequent detailed description, read together with the figures, andfrom the claims (which follow the detailed description).

A clutch lockout includes posts to receive bolts to retain the lockoutto a clutch boss and retaining screw holes to retain lockout fingersmounted on the lockout. At least one indent in each post accommodatesthe retaining screw holes and/or countersinks thereof. At least one edgeof the lockout is formed to create lips around slots to receive thelockout fingers. The lips may have a width narrower than the diameter ofthe retaining screw holes and/or the countersinks thereof. The lockoutmay comprise two retaining screw holes for each lockout finger.

BRIEF DESCRIPTION OF THE DRAWINGS

The headings provided herein are for convenience only and do notnecessarily affect the scope or meaning of the claimed invention.

In the drawings, the same reference numbers and acronyms identifyelements or acts with the same or similar functionality for ease ofunderstanding and convenience. To easily identify the discussion of anyparticular element or act, the most significant digit or digits in areference number refer to the figure number in which that element isfirst introduced.

FIG. 1 is a front view illustration of a prior art clutch lockout.

FIG. 2 is a back view illustration of a prior art clutch lockout.

FIG. 3 is a side view illustration of a lockout finger.

FIG. 4 is a front view illustration of an embodiment of a clutchlockout.

FIG. 5 is a back view illustration of an embodiment of a clutch lockout.

FIG. 6 is a side view illustration of an embodiment of a clutch lockout.

DETAILED DESCRIPTION

The invention will now be described with respect to various embodiments.The following description provides specific details for a thoroughunderstanding of, and enabling description for, these embodiments of theinvention. However, one skilled in the art will understand that theinvention may be practiced without these details. In other instances,well known structures and functions have not been shown or described indetail to avoid unnecessarily obscuring the description of theembodiments of the invention. References to “one embodiment” or “anembodiment” do not necessarily refer to the same embodiment, althoughthey may.

Unless the context clearly requires otherwise, throughout thedescription and the claims, the words “comprise,” “comprising,” and thelike are to be construed in an inclusive sense as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” Words using the singular or pluralnumber also include the plural or singular number respectively.Additionally, the words “herein,” “above,” “below” and words of similarimport, when used in this application, shall refer to this applicationas a whole and not to any particular portions of this application. Whenthe claims use the word “or” in reference to a list of two or moreitems, that word covers all of the following interpretations of theword: any of the items in the list, all of the items in the list and anycombination of the items in the list.

FIGS. 4-6 are front, back, and side view illustrations, respectively, ofan embodiment of a clutch lockout 400. Posts 410 are formed with indents411. The posts 410 include holes 412 to receive bolts to mount thelockout 400 to the clutch boss. Countersink holes 414 receive heads ofthe tightened bolts.

Fingers 300 may be inserted into the slots 402 of the lockout 400 and afinger pivot (e.g. the pivot through finger holes 302) may be recessedinto the slots 404. Retaining screws may be threaded into the holes 420,and tightened until their heads are recessed into the countersinks 418,which may overlap the slots 402, thus securing the finger pivots in theslots 404. The indents 411 in the posts 410 accommodate the holes 420and/or the countersinks 418 of the holes 420, and enable positioning theholes 420 back from the edges 406, 408 of the lockout 400. Positioningthe holes 420 back from the edges 406,408 enables the removal of asubstantial amount of material, forming lips 416 around the slots 402,without compromising the durability of the lockout 400. Material may beremoved from the lockout 400 to form the edges 406,408, and to createlips 416 having a width narrower than the diameter of the countersinks418 of the holes 420 to receive the retaining screws. The lips 416 mayeven have a width narrower than the diameter of the holes 420themselves. The edges 406,408 may form lips 416 having two portions602,604, one portion narrower than the other. Two holes 420 andcountersinks 418 may be provided per finger pivot, securing the fingerpivots at two positions of the slots 404 and further improvingdurability.

Further weight reductions are achieved by forming a hole 422 and bays424 in the lockout 400.

Other embodiments may comprise additional or fewer posts 410, andadditional or fewer slots 402,404 for fingers 300 and pivots,respectively. In light of this disclosure, these and other modificationswill now become apparent to those skilled in the art.

1. A clutch lockout comprising: posts to receive bolts to retain thelockout to a clutch boss; retaining screw holes to retain lockoutfingers mounted on the lockout; and at least one indent in each post toaccommodate the retaining screw holes.
 2. The lockout of claim 1,further comprising: slots to receive the lockout fingers; and at leastone edge formed to create lips around the slots, the lips having a widthnarrower than the diameter of countersinks of the retaining screw holes.3. The lockout of claim 2, further comprising: the at least one edgeformed to create lips having a width narrower than the diameter of theretaining screw holes.
 4. The lockout of claim 1, further comprising:slots to receive pivots of the lockout fingers; and two retaining screwholes for each slot to receive a pivot.
 5. The lockout of claim 4,further comprising: countersinks of the retaining screw holesoverlapping the slots to receive pivots.
 6. The lockout of claim 2,further comprising: two edges forming lips with portions havingdifferent widths.